Quest Minivan GLE V6-3.3L (VG33E) (1999)
Ambient Temperature Sensor / Switch HVAC: Description and Operation
The ambient temperature sensor is located on the radiator core support. It detects ambient temperature and converts it into a resistance value, which is
then input to the EATC unit.
AMBIENT TEMPERATURE INPUT PROCESS
The EATC unit includes a processing circuit for the ambient temperature sensor input. When a temperature increase less than 12°C (20°F) is
detected by the ambient temperature sensor, the processing circuit allows the EATC unit to recognize the temperature increase after 80 seconds.
When the temperature increase is greater than 12°C (20°F), 5 minutes is required.
As an example, consider stopping for a cup of coffee after high speed driving. Even though the actual ambient temperature has not changed, the
temperature detected by the ambient temperature sensor will increase because the heat radiated from the engine compartment can radiate to the
front grille area where the ambient temperature sensor is located.